Exporting world for server

I am looking for ideas for a way of exporting a game world including models on the terrain.

My current implementation can take the raw heightmap data from a terrain, then using a program I made I convert that into a serious of coordinates that I can then use in a server. This has been working and while everything is still barebones I want to work out how to export a more detailed world including the models of objects I have placed in the world.

The purpose of this would be able to allow the server to make informed decisions when a user says they want to move somewhere, currently, there is no way to tell if they want to walk into or through a wall.

Does anyone have any suggestions?